Georgia Department of Natural Resources

Environmental Protection Division  Air Protection Branch

4244 International Parkway  Suite 120  Atlanta  Georgia 30354

404/363-7000  Fax: 404/363-7100

Mark Williams, Commissioner

Judson H. Turner, Director

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June 29, 2012

Air and Radiation Docket

Attention: Docket ID No. EPA-HQ-OAR-2010-1059

Environmental Protection Agency

Mail Code: 6102T

1200 Pennsylvania Avenue NW

Washington, DC 20460

Subject: Comments on 1-hour SO2 NAAQS Implementation White Paper

Dear Docket Coordinator:

The Georgia Environmental Protection Division (EPD) appreciates the opportunity to provide 

the following comments on the U.S. Environmental Protection Agency (EPA) Office of Air and 

Radiation’s draft white paper on implementation of the 2010 primary 1-hour sulfur dioxide (SO2) 

National Ambient Air Quality Standard (NAAQS). We greatly appreciated the opportunity to 

participate in the state, tribal and local agencies stakeholder meeting held in Durham, North 

Carolina on May 31, 2012, to discuss implementation of the 1-hour SO2 NAAQS. We believe 

this type of process for NAAQS implementation is critical because most NAAQS

implementation gets done at the state, tribal, and local levels.

EPA’s draft white paper posed a number of key questions to solicit specific input from 

stakeholders. All of EPA’s questions from the draft white paper are specifically addressed in 

Attachment A of this letter.

Nonattainment Designations

Nonattainment designations should always be based on quality-assured ambient monitoring data. 

There must be ambient data demonstrating that SO2 levels are above the standard before EPA 

initiates designation of any area as not attaining the standard. Modeling should never be used to 

designate an area nonattainment in the absence of ambient data exceeding the standard. This 

applies to initial nonattainment designations and any subsequent nonattainment designations, 

should there be any. Modeling could be used to help determine the boundary for the 

nonattainment area.

Section 110(a) Infrastructure Requirements.

We agree with EPA on the revised approach for the SO2 infrastructure SIPs as described in 

EPA’s April 12, 2012 letter to state environmental commissioners. In that letter EPA stated that 

they no longer expected the infrastructure SIP submittals to contain modeling demonstrations 

showing attainment of the standard in unclassifiable areas. We believe that the criteria for such 

SIPs should be identical to the criteria for traditional infrastructure SIPs for all other criteria 
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pollutants. These SIPs should only be required to demonstrate that the state has the necessary 

legal authority, resources and programs in place to implement the new standard. As EPA has 

stated on numerous occasions, the section 110(a) SIP elements are general information and 

authorities that constitute the infrastructure of the air quality management program, much of 

which has been in place since the initial SIPs were submitted in response to the Act of 1970.

Monitoring Based Phased Implementation Approach with Exemption Based Modeling

If EPA decides that additional monitoring, such as source-oriented monitoring, is needed, then 

the additional requirements should be established through the rulemaking process with an 

adequate opportunity for public comment. The implementation schedule should consider 

available resources. With that in mind, a structured phase-in schedule should be developed. The 

phase-in schedule for source-oriented monitoring could be prioritized based upon an actual 

emissions threshold. 

As part of the rulemaking for the source-oriented monitoring provisions, EPA should include an 

exemption to this requirement. Sources should be able to use modeling to avoid the monitoring 

requirement similar to what was allowed in the lead source monitoring program except the model 

inputs should be based on typical actual conditions and the exemption should be approved if the 

model results are less than 0.075 ppm (i.e. 100% of the NAAQS). Only single, large, SO2

sources above the applicable threshold should be modeled. Any nearby small SO2 sources 

should be adequately covered by the background concentration.

If a source models at less than the standard, the source-oriented monitor should not be required. 

The 2011 Cross-State Air Pollution Rule (CSAPR), the 2011 Mercury and Air Toxics Standards 

(MATS) and the reconsidered maximum achievable control technology (MACT) standards for 

industrial, commercial, and institutional boilers (the Boiler MACT) are expected to significantly 

reduce SO2 emissions from the largest sources. Projected actual emissions after subject sources 

have installed all required emission reduction strategies should be modeled and compared to the 

standard to determine if source-oriented monitoring is necessary. 

The monitor installations should be phased in with the first phase being completed no earlier 

than two years after EPA finalizes the rulemaking establishing the monitoring requirements, 

followed by a second phase that would be completed no earlier than two years after the first 

phase. Assuming EPA completed this rulemaking by January 1, 2013, the first phase monitor 

installations would be completed by January 1, 2015. A second phase would require monitor 

installations two years after the first phase. Assuming EPA completed this rulemaking by 

January 1, 2013, the second phase would be in place by January 1, 2017.

Model Inputs

Since the purpose of this exemption from monitoring based on dispersion modeling approach is 

to represent actual ambient conditions, it is critical that the model inputs be representative of 

typical actual conditions and should not be overly conservative. The hourly emissions used in 

the model should be a realistic profile of projected actual emissions during typical operations. 

The emission inputs should not be based on allowable emissions, nor should they be based on a 
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single worst case actual emission rate. Background levels used in conjunction with the model 

results should be truly representative of background conditions that do not double count 

emissions that are already included directly in the model.

Emissions Thresholds for Phased Implementation Approach

If a state elects not to utilize the exemption based modeling approach, then the source-oriented 

monitoring criteria should be based upon an actual emission threshold. The emissions thresholds 

used in this approach should be established through rulemaking and should consider anticipated 

future SO2 emissions after full implementation of major rules impacting these emissions such as

CSAPR, MATS and the Boiler MACT along with all associated installation and operating costs. 

The thresholds should be unambiguous. If EPA establishes a threshold based on actual 

emissions and allows consideration of future SO2 emissions as described above, the threshold for 

the first phase could be as low as 2,000 tons per year. According to EPA’s draft white paper, this 

threshold would capture 93% of all point source emissions as reported in EPA’s 2008 National 

Emissions Inventory (NEI). Using the same criteria, the threshold for the second phase could be 

as low as 500 tons per year. According to EPA’s draft white paper, this threshold would capture 

approximately 97% of all point source emissions. If EPA bases the threshold on allowable 

emissions, instead of actual emissions, or if EPA bases the threshold on current emissions instead 

of future emissions then the thresholds will have to be set at much higher levels. For example, if 

EPA uses current actual emissions, the phase two threshold would have to be set at around 3,000 

tons per year and the implementation approach would not be as protective of public health 

because a significant number of medium (between 500 tons per year and 3,000 tons per year) 

sources would not be included in the implementation approach. If EPA were to set the threshold 

based on allowable emissions, there is no accurate way to assess how high the threshold would 

need to be. However, it would certainly have to be much higher than 3,000 tons per year.

EPA should provide an opportunity for sources to reduce their emissions to get below the 

applicable threshold. This would give incentive for sources to reduce their emissions below the 

threshold. This would reduce regulatory burdens on both the industry and states and the 

emission reductions would protect public health.

Monitoring Exit Strategy

We suggest that EPA establish a mechanism allowing monitors to be retired after it has been 

demonstrated that the source does not cause exceedances of the NAAQS. Considering the form 

of the standard and the difficulty in siting a limited number of monitors to capture the highest 

possible SO2 ambient levels, an appropriate level for discontinuing the operation of a sourceoriented SO2 monitor would be a three-year design value of less than 50% of the NAAQS. As an 

alternative to the 50% level, a source-oriented monitor should be allowed to retire if the threeyear design value is less than 85% of the NAAQS and the source’s emissions have been reduced 

to below the level requiring the initial installation of the monitor. Finally, the monitor should be 

allowed to retire if exemption modeling is completed showing compliance with the NAAQS at 

all ambient receptors. This exit strategy for monitoring should be clearly defined in the 

monitoring rulemaking.
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One critical flaw in EPA’s lead NAAQS source-oriented monitoring strategy is that EPA did not 

establish a reasonable monitoring exit strategy. Our source-oriented monitors in Georgia are 

consistently showing lead levels at less than 10% of the NAAQS and yet EPA continues to 

require that those monitors remain in place.

Funding for SO2 Implementation

Securing the financial resources and personnel resources to implement the SO2 NAAQS could be 

the most significant challenge to successful implementation. It is unrealistic for EPA to expect 

the states the cover a significant portion of these costs without significant increases in the state 

air grants. Given the financial challenges of most state environmental agencies, we believe that 

EPA should, at a minimum, fund the initial costs (through the phase 2 deadline) through Section 

103 grants. If EPA is unable to provide significant increases in the state air grants, EPA is 

strongly encouraged to look for other ways to secure the necessary financial resources.

Conclusion

Thank you for the opportunity to provide input on this important issue. These comments were 

carefully constructed to ensure public health protection taking into consideration the resources 

that are available to do this complex work. Additionally, EPD supports the comments on this 

subject submitted by the nine southeastern states air directors. Please contact me at 404-363-

7016 or james.capp@dnr.state.ga.us if you have any questions or wish to discuss any of the 

recommendations described in these comments.

Sincerely,

James A. Capp

Chief, Air Protection Branch

Georgia Environmental Protection Division
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Attachment A

This detailed comment listing is organized by the various section titles of the draft white paper 

that was posted to EPA’s web page on May 22, 2012. Language taken directly from the white 

paper is highlighted in italics to help provide context for the comments on that particular section. 

In particular, the White Paper poses a number of key questions for stakeholders to consider. All 

of EPA’s key questions are addressed in this letter.

Monitoring Options: Key Questions 

a. Are the conceptual monitoring networks described in the white paper sufficient to determine 

whether ambient SO2 levels meet the NAAQS and are protective of public health without the need 

for additional modeling? If not, then what enhancements should be made to them? In what 

situations should meteorological data collection also be required? 

Yes. Since a very high percentage of SO2 emissions come from a relatively small number of 

sources, focusing the monitoring network on the largest sources of SO2 (after implementation of 

the EGU MACT and Industrial Boiler MACT) will provide a reasonable assurance that ambient 

SO2 levels meet the NAAQS and are protective of public health. As described elsewhere in this 

letter, states should have flexibility to use modeling in lieu of ambient monitoring should that be 

determined by the state to be a better and/or lower cost option. Meteorological data should not 

be required as part of any SO2 ambient monitoring requirement.

b. What is an appropriate number of monitors to site around a source to assess air quality? 

This question requires consideration of both economic and technical issues. Given the fiscal 

realities that EPA and states are facing, EPA should first evaluate whether or not there are likely 

to be adequate resources to install at least one monitor at each of the large SO2 sources subject to 

the source-oriented ambient monitoring requirements. If it is unlikely that there will be more 

than adequate resources to install at least one monitor at each site, then one may be all that is 

realistic to require at this time. If EPA has identified a secure and steady stream of finances that 

would support more than one monitor, then EPA could do a technical evaluation to determine 

how many additional monitors would be advantageous for a more robust monitoring network. 

EPA should not expect states to cover the costs associated with any additional ambient monitors.

c. Is it reasonable for states to consider relocating monitors within their states?

Yes. Whenever EPA reassesses a NAAQS for a particular pollutant it is reasonable for EPA to 

revisit the monitoring network requirements for that pollutant. Any changes to the monitoring 

network requirements should take into consideration cost, time necessary to make the changes, 

impacts/concerns from local communities that may lose a monitor, as well as the ability for the 

network to provide a reasonable assurance that the NAAQS is being met and that public health is 

being protected.

What are potential barriers to relocation (e.g., cost, agreement with local community)?
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Cost and local community concerns are potential barriers to relocation. Time constraints are also 

a potential barrier because the establishment of new monitoring sites and the relocation of 

monitors is a very resource intensive task, particularly when this is happening with multiple 

monitoring sites (and possibly with multiple pollutants) simultaneously.

Is it reasonable for states to consider transferring their monitors to other states? 

No, it is not reasonable for EPA to assume that states will consider transferring their monitors to 

other states.

d. What kind of modeling (or other analyses) would be necessary to identify the location of 

maximum impact? What information and resources are necessary to complete such modeling? 

What is a reasonable schedule for completing this modeling? 

Basic dispersion modeling could be done to locate the area of maximum ambient impact. There 

may be other, lower cost, methods. EPA should continue to accept comments on these 

alternatives as it goes through the rulemaking process. As described elsewhere, states would 

need at least two years from the time that EPA completed rulemaking to establish the sourceoriented monitoring requirements to get the first phase of monitors sited. States would need at 

least two additional years after the first phase to get the second phase of monitors established. 

The modeling (or other method) to identify the location of maximum impact would be completed 

within those time periods.

e. What options exist for paying for the expanded SO2 monitoring network? Would stakeholders 

be willing to conduct monitoring at new locations or provide funding to assist states in 

conducting such monitoring? If so, what type of agreement would be needed between states and 

stakeholders to ensure the monitoring would be done? 

The financial resources and personnel resources that would be necessary to install and operate an 

expanded SO2 monitoring network (or do the exemption modeling) could be the most significant 

challenge to successful implementation of the SO2 NAAQS. It is unrealistic for EPA to expect 

the states the cover a significant portion of these costs without significant increases in the state 

air grants. Given the financial challenges of most state environmental agencies, we believe that 

EPA should, at a minimum, fund the installation costs for all additional SO2 monitors required 

by EPA through Section 103 grants. If EPA is unable to provide significant increases in the state 

air grants, EPA is strongly encouraged to look for other ways to fund an expanded SO2

monitoring network. If EPA chooses to advocate source funding, we believe EPA should 

provide a mechanism for that funding to come to the states so that the states can operate the 

monitors as part of their own monitoring network. 

f. For potential stakeholder operated monitors, what kind of oversight would the states need to 

perform? Would EPA perform additional oversight? Would someone audit these facility 

monitoring programs and associated monitors? What type of agreement would be needed 

between the states and stakeholders to insure the monitoring was carried out? How can we best 

ensure that these data are made public (e.g., require submittal to AQS)? 
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If EPA chooses to allow or require the large SO2 sources to install and operate the monitors 

themselves, states should be given full oversight to validate that monitoring is carried out 

according to acceptable practices through establishment of a Quality Assurance Project Plan 

(QAPP). Data submittal to AQS should be required. However, as discussed in the response to 

the previous question, our strong preference is to operate the monitors as part of our own 

monitoring network. We believe the overall costs will be substantially less if we operate the 

monitors than if we have to oversee the sources’ operation of the monitors.

Modeling Options: Key Questions 

a. Should some criteria (e.g., the population weighted emissions index (PWEI) concept) be used 

to identify priority sources to be modeled in an area where there is no nearby monitor? 

We favor a monitoring based implementation approach that includes an exemption from the 

monitoring based on a passing modeling analysis. The decision to take the modeling based 

exemption path would be made by the states on a case-by-case basis as to what option works the 

best for them taking into consideration implementation costs, feasibility of modeling for that 

source and for that location, and input from affected stakeholders, including the source itself. 

We do not advocate using PWEI to prioritize work. We favor the use of an annual emission 

threshold (tpy) to prioritize the work. This threshold should be based on actual emissions in 

conjunction with anticipated future SO2 reductions from major rules such as the 2011 Cross-State 

Air Pollution Rule (CSAPR), the 2011 Mercury and Air Toxics Standards (MATS), and the 

reconsidered Boiler MACT rules. States do not have the resources to evaluate facilities at 

current emission levels when these facilities will install new SO2 controls, undergo a fuel switch, 

or will be retired in the near future as a result of these rules.

EPA should provide an opportunity for sources to reduce their emissions to get below the 

applicable modeling and/or monitoring threshold. This approach provides a clear incentive to 

reduce emissions below the threshold in a timely manner and would result in emission reductions 

that would help protect public health. Furthermore, it would reduce the regulatory burdens on 

both industry and the states.

b. How should the modeling be performed – i.e., what changes to the March 24, 2011 guidance 

should be made, such as the use of size cut-offs and use of actual emissions? 

If the exemption modeling path is selected by the state, then:

1. EPA must allow states adequate time to acquire on-site meteorological data if the state or 

facility believes that on-site meteorological data would produce more accurate results.

2. EPA must allow the use of actual emission rates and statistically representative emissions 

profiles when these data are deemed to be sufficiently reliable. 

3. EPA must allow states to use background levels that are truly representative and that do 

not double count emissions that are already included directly in the model.

4. If a source is modeled out of compliance, allow them to remedy the situation through 

permitting or through installation of a source-oriented monitor.
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c. Are there situations where modeling is preferable to monitoring? If so, then what are these 

situations? Should EPA require modeling in certain situations, or is monitoring alone always a 

sufficient option for areas of concern? 

EPA should not require modeling in any situation. Monitoring should be the default requirement 

with an option to be exempted from the monitoring based on a modeling demonstration showing 

compliance with the NAAQS. States may choose the modeling approach in situations where the 

modeling isn’t too complicated and the cost of the modeling analysis is significantly less than the 

cost of installing and operating the monitor.

d. Are there situations where monitoring is preferable to modeling? If so, then what are these 

situations? Should EPA require monitoring in certain situations, or is modeling alone always a 

sufficient option for areas of concern? 

As stated above, monitoring should be the default requirement with an option to be exempted 

from the monitoring based on a modeling demonstration showing compliance with the NAAQS. 

e. What options exist for paying for the new modeling analyses? Would stakeholders be willing 

to conduct, or provide funding to assist states in conducting, any new modeling? If so, what type 

of agreement would be needed between states and stakeholders to insure modeling would be 

done? 

See response to question regarding options for paying for expanded monitoring network.

Implementation Options: Key Questions 

a. In what form should EPA set forth the revised approach? Would rules need to be revised? 

Which ones? How should states adopt the new approach, and how much time is needed for this? 

Any substantive requirement for expanded monitoring networks or the modeling of stationary 

sources must be set through notice and comment rulemaking. Guidance should not be used to 

establish any substantive requirement. States would need at least two years from the time that 

EPA completed rulemaking to establish the source-oriented monitoring requirements to get the 

first phase of monitors established. States would need at least two additional years after the first 

phase to get the second phase of monitors established. 

b. What is a reasonable schedule for 1) designing a sufficient monitoring network; and 2) 

deploying a new monitor or moving a monitor from an existing location? (What can be done to 

initiate monitoring as quickly as possible to collect sufficient data to make 

attainment/nonattainment determinations?) Is a phased approach useful? 

A phased approach for deploying the additional SO2 monitors would be useful in this situation 

since the amount of work, and expense, in some states is likely to be quite large. States would 

need at least two years from the time that EPA completed rulemaking to establish the sourceoriented monitoring requirements to get the first phase of monitors sited. States would need at 

least two additional years after the first phase to get the second phase of monitors established. 
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c. By what date should the modeling be completed and submitted to EPA? Is a phased approach 

useful? 

EPA should not require modeling in any situation. Monitoring should be the default requirement 

with an option to be exempted from the monitoring based on a modeling demonstration showing 

compliance with the NAAQS. This modeling would preferably be completed and submitted to 

EPA prior to the date that the SO2 monitor was required to be operational. However, this 

modeling should be allowed to be submitted at any time in order to be exempted from the 

requirement to install and operate the source-oriented monitor(s).

d. Once the modeling/monitoring data are in, how should states and EPA use these data to 

address violations in unclassifiable areas? Is redesignating the most workable approach? What 

should be the timing for these redesignations? Is the timing of the next SO2 NAAQS revision a 

consideration? 

EPA should develop a process that places an emphasis on providing a reasonable assurance that 

people have clean air to breathe. Redesignating unclassifiable areas to nonattainment is not a 

workable approach because it is overly bureaucratic and could result in delays in achieving clean 

air.

e. Alternatively, should EPA consider approaches to identify and address violations in 

unclassifiable areas that do not involve redesignating these areas as “nonattainment”? Which 

alternative approaches are most promising? 

Yes. If a source is determined to be causing a violation of the NAAQS in an unclassifiable area, 

EPA should establish an approach that reduces the source’s emissions such that compliance with 

the NAAQS is reasonably assured that does not involve redesignating the area as nonattainment. 

EPA should allow a state to address a source-oriented ambient air quality exceedance in an 

unclassifiable area using the air program permitting process. We understand that EPA believes 

some states may not have adequate current authority in their permitting programs to establish 

such permit conditions. While we do not necessarily agree with this position, we believe that 

EPA could establish such a permitting mechanism through the Clean Air Act. The permitting 

mechanism could be part of the EPA approved SIP. However, the individual permits would not

be part of the SIP. This may be the most efficient way to bring an area back into compliance 

with the NAAQS and is an appropriate federally enforceable instrument to use. Given the short 

term nature of the SO2 standard and the typical cause and effect relationship between an 

individual source of SO2 and a violating monitor, the traditional designation process is not wellsuited to efficiently address such violations. If a state does not address a violation in a timely 

manner, then EPA could proceed with designating an area as nonattainment and follow the SIP 

development process at that time.

f. Is it possible to develop an attainment determination approach that provides reasonable 

assurance that sources of concern that are causing violations will be identified and addressed? 

As described throughout this document, yes.
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g. How should EPA address unclassifiable areas with no emissions or shown to have no 

monitored or modeled violations? What requirements, if any, are appropriate to support 

designating these areas as attainment? Is this necessary? 

EPA should have a simple process for designating areas with low SO2 emissions. As described 

above EPA should establish a threshold that would address a high percentage of the national SO2

emissions. EPA should require monitoring (or as an alternative, modeling to be exempt from 

monitoring) of ambient air quality around sources with actual emissions greater than or equal to 

that threshold. Counties that have no sources above this threshold, and are not being impacted 

by significant emissions from a source in an adjacent county, should be designated attainment or 

unclassifiable/attainment. Under this scenario, only those counties with sources whose 

emissions are above the SO2 threshold (or are nearby such a source) should be designated 

unclassifiable and they should only be maintained in that classification until ambient monitoring 

(or exemption modeling) determines the area is attaining or violating the SO2 standard. The 

Clean Air Act contains no deadlines for states that have areas designated as unclassifiable to be 

redesignated to attainment. As such, EPA should not impose any such deadline on these areas.